The present invention relates to systems for accurately locating mobile devices, and in particular to a system providing location-aware visible light communication.
Increased use of light emitting diodes (LEDs) to provide for the primary environmental lighting in buildings and the like (termed herein “ambient lighting”) has raised the possibility of using these lights for data communication. Such data communication systems take advantage of the ability of the LEDs to switch on and off at a high rate of speed imperceptible to human eyes but suitable for communicating data. The IEEE 802.1 5.7 standard has established a basis for visible light communication protocols allowing communication of up to 96 megabits per second.
While such visible light communication is practical for point-to-point communication with a stationary device, ideally, such a system could supplant standard wireless radio communication used for mobile devices such as cell phones and the like. Extending visible light communication to such devices, however, raises a number of problems including sharing bandwidth when multiple users are present and shadowing of the mobile device (for example, by the user's body).